In LTE (Long Term Evolution) and successor systems of LTE (referred to as, for example, “LTE-advanced,” “FRA (Future Radio Access),” “4G,” etc.), a radio communication system (referred to as, for example, “HetNet” (Heterogeneous Network)) to place small cells (including pico cells, femto cells and so on) having a relatively small coverage of a radius of approximately several meters to several tens of meters, in a macro cell having a relatively large coverage of a radius of approximately several hundred meters to several kilometers, is under study (see, for example, non-patent literature 1).
For this radio communication system, a scenario (“co-channel deployment”) to use the same frequency band F1 in both the macro cell and the small cells as shown in FIG. 1 and a scenario (“non-co-channel deployment,” “separate frequency deployment,” etc.) to use different frequency bands F1 and F2 between the macro cell and the small cells are under study. Also, a scenario to form a small cell cluster with a plurality of small cells without placing a macro cell (without macro coverage) is also under study.